Each day, a tidal wave of good will sweeps movie stars out of their Hollywood homes and onto the banks of the Potomac, where they lobby for the causes closest to their hearts. Thursday’s castaway:Hayden Panettiere.

Venue: The White House.

Event: A meeting with Nancy Sutley, of the White House Council on Environmental Quality

Cause: To save the whales.

Bona fides: Played a super-human cheerleader on TV’s “Heroes”; disrupted a 2007 Japanese dolphin hunt with fellow activists.

What she wants: To thank President Obama for taking diplomatic action Thursday to prod Iceland to ban hunting of whales and exporting of their meat.

Wingmen:Jeff Pantukhoff, president of the Whaleman Foundation; Monica Medina, U.S. commissioner for the International Whaling Commission.

How she sounded: Determined and thoughtful — though Medina swept her aside when it came time to talk details.

Anecdote: Panettiere says she first buttonholed Obama about whaling back during the 2008 campaign. “He said that he was from Hawaii and that he had spent so much time with dolphins and whales and that they were like this,” explained Panettiere, aiming two fingers at her pupils.

Who we missed for her:Barry Manilow on atrial fibrillation awareness; Tray Chaney (Poot from “The Wire”) for marijuana legalization.